Buoyancy compensation

ABSTRACT

A buoyancy pillow for a free diver is attached to the ventral side of a diver&#39;&#39;s trunk by shoulder, waist and crotch straps, the pillow including a bladder with a center of buoyancy located in its lower one-half portion when inflated by the diver from a hose equipped with a mouthpiece having valve structure including a pressure-relief valve.

United States Patent 11 1 Braly .luly 24, 1973 [54] BUOYANCYCOMPENSATION FOREIGN PATENTS OR APPLICATIONS 1 lnvemofl Edmul1d Braly;756 Alto Vista 1,293,158 4/1962 France 9/316 Dr., Pac1fica,Cal1f.883,100 7 1953 Germany 9 313 Filed Oct 6 1971 P13903 12/1956 Germany9/333 [21] Appl. No.: 186,973 Primary E xaminer-Milton Buchler AssistantExaminerPaul E. Sauberer [52] U 8 CI W313 Attorney-Flehr, Hohbach, Test,Albritton & Herbert [51] Int. Cl. B63c 11/18, B630 9/08 58 Field 01Search 9 311, 313, 314, [57] ABSTRACT 9,316, 329442 A buoyancy p1l1owfor a free d1ver 1s attached to the ventral side of a divers trunk byshoulder, waist and [56] References Cited crotch straps, the pillowincluding a bladder with a center of buoyancy located in its lowerone-half portion UNITED STATES PATENTS when inflated by the diver from ahose equipped with g fig'azl zz j 9/ a mouthpiece having valve structureincluding a pres- 31337Iss7 1 8/1967 Barnier 9/313 sure'mhef valve3,436,777 4/1969 Greenwood 9/313 X 6 Claims, 6 Drawing Figures mimemumms 33471139 sum 2 or 2 ,4rraeA/srs BUOYANCY COMPENSATION BACKGROUND OFTHE INVENTION This invention pertains to buoyancy compensation for freedivers and specifically relates to a buoyancy pillow worn by the diveron the front of his trunk and inflatable and deflatable by him foradjusting his buoyancy in the water.

Buoyancy compensators in the art have been derived from the inflatablelife vest and for that reason have a number of shortcomings. Morespecifically, the life vest type compensators invariably have an aircompartment which encircles the neck of the wearer providing buoyancybehind the head and neck. While buoyancy in this region may be highlydesirable in a life vest, when such a vest is worn in an inflatedcondition by a diver, it has the undesirable effect of tending to urgethe head towards an upright attitude which makes swimming movements onthe water surface inefficient and laborious to the free diver with hisequipment.

Another deficiency of prior buoyancy compensators is that the inflationhoses which were provided so that the diver could orally inflate thevest were connected to the vest in an awkward position behind the divershead to obviate trapped air in the vest. In this location the inflationhoses would frequently interfere with the divers air breathingequipment. A furthershortcoming was 'that inflating the vest underwaternecessitated blowing a quantity of water from the mouthpiece through arelatively long hose to the vest inlet behind the-divers. neck. In theoperation, the diver exerted himself unnecessarily and following use ofsuch vest during a days-dives, the inflating operation would entrap asignificant volume of water in the vest. Portions of this water wasadmitted each time the diver orally inflated the vest with the result ofreducing the buoyancy capacity of the vest and diminishing its capacityfor aiding the diver to regulate his buoyancy. Moreover, the prior artbuoyancy compensators had a high center of buoyancy located near thedivers chest. This tended to rotate the diver towards an undesiredvertical attitude when surface swimming and placed the'buoyant forceupon the chest making chest expansion for breathing difficult.

SUMMARY OF THE INVENTION AND OBJECTS In summary, the present inventionin a buoyancypillow comprises an inflatable air bladder having strapmembers for attachment to the ventral side of a divers torso forlocation entirely beneath the chin and above the crotch. An airinflation hose having a mouthpiece assembly arranged to communicate withthe bladder at the highest portion thereof, the mouthpiece beingequipped with valve means including a pressure-relief valve. The bladderis shaped so as to locate the center of buoyancy in the lower halfthereof. I An object of the invention is to provide an improvedapparatus through the use of which afree diver may compensate hisbuoyancy in the water so as easily to maintain his'torso in any selectedattitude but most easily in a generally horizontal attitude whilesurface swimming.

Another object of the invention is to provide a buoyancy pillow arrangedfor oral inflation and which will entrain an insignificant volume ofwater after numerous submersed inflation-deflation cycles.

Another object of the invention is to provide an improved buoyancypillow which is configurated so that its center of buoyancy is disposedin the lower region of the divers torso.

Further objects and features of the invention will appear from thefollowing description taken in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a free diverswimming in a body of water and having mounted on the anterior of historso the buoyancy pillow of the present invention;

FIG. 2 is an enlarged perspective view taken from the front side of thebuoyancy pillow shown in FIG. 1;

FIG. 3 is a view like FIG. 2 showing the posterior side of the buoyancypillow;

FIG. 4 is an enlarged sectional view taken along the line 4-4of FIG. 3;and

FIGS. 5 and 6 are side and front views respectively of the buoyancypillow.

DESCRIPTION OF THE PREFERRED EMBODIMENT A buoyancy pillow 10 accordingto the present invention is shown in FIG. 1 of the drawings operativelymounted on the ventral side of the trunk of a free diver 11. In additionto the buoyancy pillow 10, the diver 1 1 is equipped with conventionalSCUBA (self-contained underwater breathing apparatus) equipmentincluding an air tank 12 equipped with an air pressure regulator 13which permits pressurized air to flow through a breathing hose 14communicating with a mouthpiece 16 which the diver 11 can maintain inhis mouth for breathing. Further, the diver is equipped with abodyencompassing wetsuit 17, fins 18 and a weight belt 19 for offsettingthe buoyancy of the wetsuit 17 at shallow depths before the cellsthereof are compressed from ambient hydrostatic pressure. A diving mask21 diverthe divers nose and eyes is worn over the hood portion of thewetsuit. With the exception of the buoyancy pillow 10 of the presentinvention, the above enumerated equipment is well-known and understoodin the art and is commonly employed by free divers.

Referring to FIGS. 2 and 3, the buoyancy pillow 10 includes aninflatable bag or bladder 26 formed from front 27, back 2% and medialpanels 29. The panels 27-29 preferably consist of rubberized fabriccemented or vulcanized together on overlapped portions 31 to defineair-proof and water-proof seams. The front 27 and back 28 panels may beidentical in outline and the medial or side panels 29 may be shaped togive the bag a desired tapered form when viewed from the side, (FIGS. 1and 5) the bag being wider at the bottom portion than at the top, asshown best in FIGS. 2 and 6. The front and back panels have an outlinewhich is generally ovoid or parabolic in the upper two-thirds tothree-quarters of the panels. From the lower one-third to one-quarter ofthe panels 27 and 23 the outline generally resembles an ellipse cut atthe long axis. It should be recognized that the configuration of thepillow may be varied somewhat from that illustrated herein, but is veryadvantageous that the pillow be shaped and sized to provide, when fullyinflated, a buoyancy of 40 to 45 pounds in the water with the center ofbuoyancy located in the lower one-half and preferably close to the lowerone-third region of the bladder. The amount of inflated buoyancy for thebladder is selected in relation to the weight of the divers air tankequipment 12-14 which, when the diver swims on the surface, placesdownward forces on the divers torso tending to make breathing laborious.An air pillow having buoyancy in the 40 to 45 pounds range is used withair tank equipment weighing about 37 pounds. Thus, depending upon thebuoyancy of the divers body and the attached SCUBA equipment, there willbe available for surface swimming from 3 to 8 pounds of positivebuoyancy by reason of the buoyancy pillow.

As expressed above, the upper portion of the bladder 26 is ovoid inoutline so that the top portion of the bag has an apex or high point 34,at which location a pillow inflation hose 36 is secured in communicationwith the bladder 26, FIGS. 2 and 6. More particularly, a coupling 39 isarranged at the apex 34 of the bag 26 (FIG. 2) and the inflation hose 36is secured to the coupling 39 so as to establish an air-tight andwater-tight connection between the hose 36 and the bag 26. A hose clamp40 (FIG. is satisfactory to maintain the hose in operative associationwith the coupling 39.

The breather hose terminates in a generally L-shaped mouthpiece assembly38 (FIG. 4) which will be described in detail below. The breather hose36 may be of rubberized corrugated construction and may have a nominalinside diameter on the order of 0.75 inches. Because the highest point34 of the bladder will reside near the divers chin, the hose 36 may bemade quite short, as compared to the prior art, on the order of from 4to 6 inches long.

To ensure that the buoyancy pillow is maintained at the desired positionagainst the ventral side of the divers torso or trunk, an assembly ofbody-encircling straps is provided. This includes a waist strap 41 andleft 42 and right 43 shoulder straps which join the waist strap 41 in asleeve 44 (FIG. 3) slidable with respect to the waist strap 41. A crotchstrap 46 unites at its upper end with the sleeve 44 and at its lower endis equipped with a snap clip 48 coope'rable with a ring 47 secured tothe bladder by the tang strip 49. The crotch strap functions to preventthe air pillow from shifting upwardly on the divers trunk. So as toprovide clearance for the divers weight belt 19, the tang strip 49carrying the ring 47 for connection to the slip 48 is mounted on theback panel 28 of the bladder a distance above the bottom of the bag, asclearly shown in FIG. 3. The strip 49 may be mounted at the panel 28 bycementing the strip 49 to the back panel 28.

Considering the waist belt 41, a ring 51 and snap clip 52 assembly isprovided for linking the bladder with the waist strap or belt 41 to thedivers trunk. The upper ends of the shoulder straps 42 and 43 are eachsecured to the upper portion of the back panel 28. The right handportion of the waist belt 41 is attached to the rear panel 28 of thebag. Buckles 56 for adjusting the length of each of the straps are alsoprovided. Thus, the buoyancy pillow 10 may be accommodated to divers ofvarying physical sizes by selective adjustment of the straps so that theair pillow may be held in the desired and preferred location on thedivers trunk to extend on the chest to just above a line drawn throughthe nipples and downwardly to about a lateral line drawn through the hipjoints.

The mouthpiece assembly 38, best shown in FIG. 4, is constructed toinclude a valve mechanism which the diver may manipulate so that he mayinflate the air bag 26 by expelling his breath through the mouthpiecesuch as for equalizing the divers buoyancy when submerged; and similarlyfor releasing air from the bag when ascending from a sub-surface depthin the water. A provision is included in the mouthpiece forautomatically releasing air from the bag so as to prevent the bag fromrupture should the diver be inattentive or incapable of manipulating thevalve during ascent. The arrangement of the mouthpiece 38 is such thatthe bag may be inflated and deflated a great number of times during adays diving without entraining any significant volume of water into thebag through the mouthpiece.

More particularly, the mouthpiece assembly 38 includes a generallyL-shaped housing 57 connected at one end to the breather hose 36 andsecured thereto by an encircling hose clamp 58. At the other end, thehousing is fitted in an air-tight manner in a cup portion 59 of a mouthinsert member 61 which the diver seals between his lips for blowing airinto the mouthpiece assembly. The member 61 is arranged immediatelyadjacent to an axially shiftable valve disc 62 which the divermanipulates by depressing in a squeezing action a valve plunger rod 63connected at one end to the valve disc. Inward movement of the rod 63 isresisted by the bias of a length of rubber tubing 64 which functions asa compression spring. In the closed condition shown in FIG. 4, the valvedisc 62 seats against a spool 66 arranged inwardly of the mouth insertmember 61, the innermost end 67 of the spool 66 serving as an axialguide for the valve rod 63. The spool end 67 is also provided with aplurality of air passageways 68 so that when the diver presses upon therod 63 to move the valve disc from sealing engagement with the spool, hemay expel air into the mouthpiece housing 57 through a passageway 70 andthe air holes 68 and thence into the bag. A radially disposed array ofribs 69 is located on the inner face of the cup portion 59 to preventthe disc 62 in the forward or open condition from sealing the air inletpassageway 70. Thus, when the diver depresses the plunger rod 63 toplace the disc 62 against the ribs 99, air will be expelled from the bagin response to ambient water pressure to the end that the buoyancypillow may be deflated.

The pressure-relief valve function is provided in the mouthpieceassembly by the relationship of the area of the valve disc 62 exposed tothe internal pressure of the bladder and the compression constant of therubber spring 64. The area of the valve disc and spring constant areselected so that when the internal pressure of the air bag exceeds theambient or outside water pressure on the opposite side of the valve discby about onequarter atmosphere, the valve disc will shift from its seaton the spool to an open condition and automatically permit the expandedair to leave the bag through the mouthpiece 61.

It will be recongnized that the valve disc operates in a chamber 72 ofminimal volume being that the chamber of the cup portion is onlyslightly larger in diameter than the disc 62 and only as long as thestroke of the disc. This configuration, together with the small volumeof the air inlet passageway, provides the advantageous feature that asthe diver opens the valve and blows into the bag, a minimum volume ofwater will be carried into the bag. Thus, at the end of a day's diving,the amount of water in the bag will be an insignificant amount, on theorder of two cupfuls.

To maintain the mouthpiece assembly in a desired out-of-the-way positionwhen not in use, a Velcro brand of fabric assembly 74 (comprisingsynthetic materials which adhere when pressed together, as is wellknownin the art and as shown and described in U. S. Pat. Nos. 2,717,437,3,154,837, 3,147,528, 3,076,244 and 3,009,235) is arranged on the pillowinflation hose 36 and the right shoulder strap 43 so that the diver maysimply engage the breather hose with the shoulder strap and the Velcroassembly portions will lockingly engage and maintain the air hose uponthe right shoulder strap in an unobstrucing out-of-the-way position(FIGS. 2 and 3).

OPERATION The buoyancy pillow may be utilized by the diver when restingor moving on the water surface to equalize his buoyancy or to ascend ina controlled fashion from depth without having to exert himself undulyhard, e.g., to float to the surface without kicking and at a proper rateof ascent such as 60 feet per minute.

When the diver uses the air pillow on the surface, such as when swimmingbetween the shore and an offshore diving buoy, the diver orally inflatesthe air bag, first removing the mouthpiece assembly from its securedposition on the right shoulder strap and then expelling his breath intothe bag through the mouth insert member 61 upon depressing the valve rod63. The bag or bladder 26 may be fully inflated to provide the diver andhis associated equipment with positive buoyancy. In this condition, thediver may swim in the water with his body draped over the buoyancypillow, the head and legs drooping downwardly so that the diver maywatch and observe the bottom while breathing through his breather hose14, from the air tank and regulator 13 or from a snorkel (not shown).

As shown in FIG. I, the downward arrow 76 represents the summation ofthe vertical downward or displacement forces of the diver and hisequipment. The .arrow 77 in FIG. 1 represents the summation of buoyancyforces including the buoyancy derived from the inflated buoyancy pillowwhich itself may be on the order of 40 to 45 pounds buoyancy. Thehorizontal displacement of the arrows 76 and 77 indicates a rotationalmoment acting upon the diver tending to rotate his body towards ahorizontal attitude. This permits the diver through movement of his headto shift easily from a prone to an upright position in the water withouthaving to work against a buoyancy pocket, such as was provided by theprior art neck-encircling life vest.

When the diver reaches the location for diving, such as defined byoff-shore diving buoys, he may deflate the pillow by opening the valveby pressing onthe plunger element 63 and air is expelled from the bag inresponse to the exterior water pressure acting on the bag. The diverdescends towards the bottom with the air pillow in the deflatedcondition.

An ascent to the surface from a subsurface position .is made by thediver through use of the buoyancy pillow. In this situation, the diverfirst takes a breath from his tank of compressed air through theregulator mouthpiece therefor and expels that breath through the pillowinflator hose 36 into the bag. The first breath of air into the buoyancypillow will not give the diver added buoyancy-because he was simplytransferring air from his lungs into the buoyancy pillow. To gainpositive buoyancy, the diver takes a second breath from his air tankwhereupon he achieves positive buoyancy from the air in his lungs addedto that in the buoyancy pillow and he then begins to ascend. Thepositive buoyancy produced through use of the pillow permits the diverto ascend in a floating movement, without the exertion of swimming orfoot-kicking, and at the desired upward rate of feet per minute. Duringascent, as air in thepillow expands, the diver should release air fromthe buoyancy pillow by depressing the valve plunger. Should the diverduring ascent neglect to release air from the buoyancy pillow andthereby tend to ascend too rapidly and tend to over expand the pillowtowards rupture, the release valve becomes operative upon creation of apressure differential between the inside and outside of the bag ofone-quarter atmosphere, or about three and three-quarters poundspressure. This is equivalent to a vertical water column of approximatelyeight feet.

In view of the above description and drawings, it will be apparent thatthere has been disclosed herein a buoyancy pillow which permits a freediver to move easily along the surface of the water and to ascend fromdepth at a controlled rate. Should the diver neglect to properly expelexpanding air from the air pillow during ascent to the water surface,the release valve is automatically activated to release air from thebag. While the specific embodiment of the invention is set forth above,the scope thereof is defined by the following claims.

I claim:

ll. A buoyancy pillow for a free diver comprising an inflatable bladder,strap assembly means secured to said bladder for holding the sameentirely against the ventral side of the torso of the divers body andincluding a waist strap member serving to encircle the divers waist, apair of shoulder strap members, and a crotch strap member, a flexibleinlet and outlet breathing hose connected to said bladder at theuppermost inflated portion thereof, said breathing hose including amanually actuatable valve permitting the entry and exhaust of air withrespect to said bladder and including a pressure-relief valve responsiveto a positive pressure differential between the internal and externalpressures on said bladder for automatically permitting discharge fromsaid bladder at a predetermined differential pressure, said strapmembers being arranged and said bladder being sized to lay against thetorso entirely within the zone between the shoulders and crotch andbeing configurated to have its greatest cross-sectional area disposed inthe lower one-half portion thereof and proximate the attachment of saidwaist strap member.

2. The buoyancy pillow of claim 1 wherein said bladder, in longitudinalcross-section, is tapered so as to provide the widest portion in thelower one-third of said bladder.

33. The buoyancy pillow of claim It wherein said pair of shoulder strapand crotch members are arranged in an interconnected wye configuration,said crotch strap member including a tang strap member secured to oneside of said bladder above the bottom portion of said bladder.

4. The buoyancy pillow of claim 1 wherein said inlet and outletbreathing hose is provided with a mouthpiece, said valve means beingarranged closely proximate said mouthpiece obviating any substantialwatercontaining void.

5. The buoyancy compensator of claim 1 wherein said flexible hose isprovided with a mouthpice assembly including valve means including avalve disc shiftable between open and closed positions in a valve cavityimmediately adjacent a mouth insertion member.

6. in a buoyancy compensator for a free diver, the combinationcomprising an inflatable bladder, a strap assembly secured to saidbladder for holding the same against the torso of the diver, and aflexible inlet and outlet breathing hose connected at one end to saidbladder and having a mouthpiece assembly at the other end, said bladderbeing formed from rubberized fabric material and including substantiallyidentical front and rear panels united along their respective peripheraledges to an intermediate panel in an air-tight and water-tight seam,said front and rear panels having a general outline of a parabola in theupper two-thirds portion thereof and the outline of an ellipse in thelower one-third portion thereof, in longitudinal cross section said bagtapering from a narrow portion at the top to a wide portion at thebottom so that said bladder has a center of buoyancy in the lowerone-third portion thereof, said waist strap member being attached tosaid rear panel of said bladder, said pair of shoulder strap members andsaid crotch member being arranged in an interconnected wye configurationwith the ends of said wye mounted on the rear panel of said bladder,said flexible hose being connected to said bladder in the upper portionthereof.

1. A buoyancy pillow for a free diver comprising an inflatable bladder,strap assembly means secured to said bladder for holding the sameentirely against the ventral side of the torso of the diver''s body andincluding a waist strap member serving to encircle the diver''s waist, apair of shoulder strap members, and a crotch strap member, a flexibleinlet and outlet breathing hose connected to said bladder at theuppermost inflated portion thereof, said breathing hose including amanually actuatable Valve permitting the entry and exhaust of air withrespect to said bladder and including a pressure-relief valve responsiveto a positive pressure differential between the internal and externalpressures on said bladder for automatically permitting discharge fromsaid bladder at a predetermined differential pressure, said strapmembers being arranged and said bladder being sized to lay against thetorso entirely within the zone between the shoulders and crotch andbeing configurated to have its greatest cross-sectional area disposed inthe lower one-half portion thereof and proximate the attachment of saidwaist strap member.
 2. The buoyancy pillow of claim 1 wherein saidbladder, in longitudinal cross-section, is tapered so as to provide thewidest portion in the lower one-third of said bladder.
 3. The buoyancypillow of claim 1 wherein said pair of shoulder strap and crotch membersare arranged in an interconnected wye configuration, said crotch strapmember including a tang strap member secured to one side of said bladderabove the bottom portion of said bladder.
 4. The buoyancy pillow ofclaim 1 wherein said inlet and outlet breathing hose is provided with amouthpiece, said valve means being arranged closely proximate saidmouthpiece obviating any substantial water-containing void.
 5. Thebuoyancy compensator of claim 1 wherein said flexible hose is providedwith a mouthpice assembly including valve means including a valve discshiftable between open and closed positions in a valve cavityimmediately adjacent a mouth insertion member.
 6. In a buoyancycompensator for a free diver, the combination comprising an inflatablebladder, a strap assembly secured to said bladder for holding the sameagainst the torso of the diver, and a flexible inlet and outletbreathing hose connected at one end to said bladder and having amouthpiece assembly at the other end, said bladder being formed fromrubberized fabric material and including substantially identical frontand rear panels united along their respective peripheral edges to anintermediate panel in an air-tight and water-tight seam, said front andrear panels having a general outline of a parabola in the uppertwo-thirds portion thereof and the outline of an ellipse in the lowerone-third portion thereof, in longitudinal cross section said bagtapering from a narrow portion at the top to a wide portion at thebottom so that said bladder has a center of buoyancy in the lowerone-third portion thereof, said waist strap member being attached tosaid rear panel of said bladder, said pair of shoulder strap members andsaid crotch member being arranged in an interconnected wye configurationwith the ends of said wye mounted on the rear panel of said bladder,said flexible hose being connected to said bladder in the upper portionthereof.